CN102399059A - Glass composition for substrate and substrate for plasma display using same - Google Patents

Abstract

The invention provides a glass composition for substrate, and the glass composition is formed by using a float glass process, has a high glass transition point and has an identical thermal expansion coefficient as soda-lime glass does; the invention also provides a substrate for plasma display using the glass composition. The glass composition contains, expressed in weight percent, 52 to 62 of SiO2, 5 to 12 to Al2O3, 3 to 5.5 of CaO, 6 to 9 of SrO, 17 to 27 of MgO+CaO+SrO+BaO, 7 to 14 of Li2O+Na2O+K2O and 0.2 to 6 of ZrO2.

Description

The plasma display of glass composition for substrate and use said composition is used substrate

Technical field

The present invention relates to as flat-panel monitor, especially plasma display (PDP) useful and be suitable for making glass composition for substrate by the large substrate of float forming with base plate glass.

Background technology

PDP is generally through following method manufacturing: under about 550 ℃～about 600 ℃ top temperature, be sintered in metal electrode, insulating paste, barrier size (rib paste) etc. on the base plate glass after, opposed plate is carried out glass powder seals (frit seal).In the past, as the base plate glass of this purposes, used usually and be widely used in soda-lime glass for building or that automobile is used.

But; Because the glass transition point of soda-lime glass is 530～550 ℃; So if under above-mentioned top temperature, accept thermal treatment; Then substrate can deform or the size of base plate glass can produce obvious variation, therefore can produce to be difficult to precision and to realize the problem with the electrode contraposition of opposed plate etc. goodly.When the size of panel when for example being called 40 inches such large-scale panels, such problem becomes more remarkable, thereby needs the higher substrate of thermotolerance to use glass.

At present, as thermotolerance be superior to soda-lime glass, as indicating meter with the widely used base plate glass of glass, for example having with japanese kokai publication hei 4-325434 (No. the 5348916th, US Patent specification) is that the liquid crystal of representative is used non-alkali glass.But the thermal expansivity of these glass is 35～50 * 10 ^-7℃ ^-1Scope in, be far smaller than 80～90 * 10 of soda-lime glass ^-7℃ ^-1Thermal expansivity.Therefore, for liquid crystal is used for PDP with non-alkali glass, various glass powder, grout material must be used the material consistent with the coefficient of thermal expansion of base plate glass, are very difficult and in the said temperature scope, select these materials.

On the other hand, in japanese kokai publication hei 3-40933, the thermal expansivity that discloses a kind of thermal expansivity and soda-lime glass is equal extent and the little glass composition of the thermal distortion under 600 ℃.But, compsn disclosed herein following can not be satisfactory fully aspect arbitrary.

(1) because glass transition point is below 600 ℃,, inadequately little by the shrinkage of the caused glass of thermal treatment therefore for being called 40 inches so large-scale panels.

(2) because the content of CaO is more than 6%, so devitrification temperature is high, is difficult to form through quality and the good float glass process of productivity.

Summary of the invention

The object of the present invention is to provide and solve above-mentioned shortcoming, have the thermal expansivity identical, be suitable for making large-scale PDP, have the high glass transition point, be suitable for the glass composition for substrate of float forming with soda-lime glass.

The present invention is a kind of glass composition for substrate, and % representes with weight, contains in fact:

SiO ₂ 52～62％

Al ₂O ₃ 5～12％

MgO 0～4％

CaO 3～5.5％

SrO 6～9％

BaO 0～13％

MgO+CaO+SrO+BaO 17～27％

Li ₂O+Na ₂O+K ₂O 7～14％

ZrO ₂ 0.2～6％

SO ₃ 0～0.6％。

Glass of the present invention can form through float glass process, and glass transition point is high in addition, and has the thermal expansivity equal with soda-lime glass, therefore is suitable for plasma body requires said characteristic with substrate etc. purposes.

Embodiment

Because float forming is to be about 10 in viscosity ⁴Pool carries out down, therefore if not devitrification temperature be lower than and 10 ⁴Moor the glass of suitable temperature, then be difficult in fact form through float glass process.

The qualification of composition of the present invention the reasons are as follows said.

SiO ₂: form the composition of the skeleton of glass, be less than 52 weight % as if its content, then the thermotolerance variation of glass.On the other hand, if surpass 62 weight %, then thermal expansivity descends.More preferably SiO ₂In the scope of 54～60 weight %.

Al ₂O ₃: have the rising glass transition point and improve stable on heating effect,, then do not show this effect if its content is less than 5 weight %; On the other hand, if surpass 12 weight %, then the thermal expansivity of glass became low.More preferably Al ₂O ₃In the scope of 6～11 weight %.

MgO: be not neccessary composition, but through containing the rising that can realize glass transition point and the increase of thermal expansivity.But,, then be prone to produce devitrification if its content surpasses 4 weight %.

CaO: have rising glass transition point and the effect that increases thermal expansivity.If its content is less than 3 weight %, then the thermal expansivity of glass becomes too small.On the other hand, if surpass 5.5 weight %, then devitrification temperature is higher than the forming temperature of float glass process, is difficult to carry out the shaping of float glass process.

SrO: likewise have rising glass transition point and the effect that increases thermal expansivity with CaO.If its content is less than 6 weight %, then the thermal expansivity of glass becomes too small.On the other hand, if surpass 9 weight %, then devitrification temperature is higher than the forming temperature of float glass process, is difficult to carry out the shaping of float glass process.

BaO: same with MgO, be not neccessary composition, but through containing the rising that can realize glass transition point and the increase of thermal expansivity.But,, then be prone to produce devitrification if its content surpasses 13 weight %.

MgO+CaO+SrO+BaO: if their total amount is less than 17 weight %, then the thermotolerance of glass descends, and it is too small that thermal expansivity becomes.On the other hand, if surpass 27 weight %, then devitrification temperature becomes too high.More preferably MgO+CaO+SrO+BaO is in the scope of 18～25 weight %.

Li ₂O, Na ₂O, K ₂O:, must contain a kind of at least in order to increase the thermal expansivity of glass.If their total amount is less than 7 weight %, then the thermal expansivity of glass is too small.On the other hand, if total amount surpasses 14 weight %, then the thermotolerance of glass descends.More preferably Li ₂O+Na ₂O+K ₂O is in the scope of 8～13 weight %.

Wherein, in order to increase the thermal expansivity of glass, preferably contain the above K of 4 weight % ₂O.On the other hand, if excessively add these compositions, then the tendency of the thermotolerance of glass decline is big.Consider from said viewpoint, more preferably with Na ₂O is set at the scope of 0～6 weight %, with K ₂O is set at the scope of 4～12 weight %, with Li ₂O is set at the scope of 0～1 weight %.

ZrO ₂: for the thermotolerance that improves glass and chemical durability and use.If be less than 0.2 weight %, then there is not additive effect, preferably add more than the 0.5 weight %.On the other hand, if its content surpasses 6 weight %, then the devitrification temperature of glass becomes too high.

SO ₃: be not neccessary composition, but use as finings usually.But if its content surpasses 0.6 weight %, then glass takes place to boil etc. again during fabrication, thereby bubble is residued in the glass.Thus, in the present invention, the example that preferred glass is formed is represented as follows in fact with weight %:

SiO ₂ 54～60％

Al ₂O ₃ 36～11％

MgO 0～4％

CaO 3～5.5％

SrO 6～9％

BaO 0～13％

MgO+CaO+SrO+BaO 18～25％

Li ₂O 0～1％

Na ₂O 0～6％

K ₂O 4～12％

Li ₂O+Na ₂O+K ₂O 8～13％

ZrO ₂ 0.5～6％

SO ₃ 0～0.6％

For fusing property, clarification property, the plasticity of improving glass, glass of the present invention is outside mentioned component, and can add total amount is the As below the 2 weight % ₂O ₃, Sb ₂O ₃, P ₂O ₅, F, Cl.In addition, in order to improve the chemical durability of glass, can add total amount is the La below the 5 weight % ₂O ₃, TiO ₂, SnO ₂, ZnO.In addition, can add Fe ₂O ₃, CoO, NiO, Nd ₂O ₃Regulate the tone of glass Deng tinting material.The content of this tinting material is preferably below the 1 weight % in total amount.

In addition, in order to improve fusing property, can add B ₂O ₃But excessively interpolation can make thermal expansivity descend, and therefore preferably is less than 1.5 weight %.

The glass transition point of the glass that obtains thus is more than 600 ℃, is preferably more than 610 ℃.In addition, to be lower than viscosity be 10 to the devitrification temperature through the resulting glass of the present invention ⁴Temperature during pool.The difference of the two is preferably more than 40 ℃.In addition, the thermal expansivity through the resulting glass of the present invention is 75～95 * 10 ^-7℃ ^-1Scope in, preferably 80～90 * 10 ^-7℃ ^-1Scope in.

Glass of the present invention is suitable as plasma display and uses substrate.Its spectral transmission is preferably more than 85% respectively in the scope of 425～475nm, 510～560nm, 600～650nm.

Glass of the present invention can be made through the method for example.That is, the raw material of normally used each composition cooperated make it reach target to form, the gained material is dropped in the smelting furnace continuously, and be heated to 1500～1600 ℃ and make its fusion.Make this melten glass be configured as predetermined thickness of slab through float glass process, and after annealing, cut, obtain transparent glass substrate thus.

Embodiment

Example 1～10 (table 1) expression embodiment, example 11～18 (tables 2) expression comparative example.

The raw material of each composition cooperated make it reach target to form, use platinum crucible, heating 4 hours is with its fusing under 1500～1600 ℃ temperature.During fusing, insert the platinum whisking appliance and stirred 2 hours, glass is homogenized.Then, the glass of fusing is flowed out, be configured as tabular after, anneal.

Weight %), thermal expansivity, glass transition point, viscous temperature and devitrification temperature for the glass that obtains like this, measure to form (first half of table 1, table 2, unit:, and be shown in each hurdle of table.Thermal expansivity is shown in the α hurdle, and unit is 10 ^-7℃ ^-1Second-order transition temperature is shown in T _gIn the hurdle, unit is ℃; Devitrification temperature is shown in the C hurdle, and unit is ℃.For viscous temperature, will be 10 with viscosity ²Suitable temperature is shown in the A hurdle during pool, and unit is ℃; To be 10 with viscosity ⁴Suitable temperature is shown in the B hurdle during pool, and unit is ℃.

Be described below and obtain glass transition point.Glass after keeping 30 minutes under the temperature of annealing point, is cooled off with 60 ℃/minute speed and to make its annealing.Then, for the glass after this annealing, use differential dilatometer in room temperature to obtaining the curve of coefficient of thermal expansion between the yield-point with respect to temperature.The tangent line that draws in the front and back that begin most crooked point of this curve, with the pairing temperature of the intersection point of tangent line as glass transition point.

Show that by table 1 thermal expansivity of glass composition of the present invention is 80～90 * 10 ^-7℃ ^-1Scope in, be equal to fully with the thermal expansivity of existing soda-lime glass.In addition, glass transition point is more than 610 ℃, in the manufacturing of large-scale PDP, problems such as glass shrinks can not occur.In addition, devitrification temperature is 10 than the shaping viscosity with float glass process ⁴It is low more than 40 ℃ to moor suitable temperature, can know the manufacturing that it is suitable for utilizing the large substrate that float glass process carries out.

On the other hand, example has been carried out same mensuration to the disclosed glass composition of japanese kokai publication hei 3-40933, and this measurement result has been shown in Table 2 as a comparison.In comparative example, the glass transition point of the glass of example 13 and example 14 is below 600 ℃, so thermotolerance is insufficient, can predict in the manufacturing of large-scale PDP to produce the problem that glass shrinks.

In addition, the glass of example 11～12,15～18, devitrification temperature all is higher than and 10 ⁴Moor suitable temperature, therefore in float forming, possibly produce devitrification.

Table 1

Table 2

Claims (9)

1. glass composition for substrate, % representes with weight, comprises in fact:

SiO ₂ 52～62％

Al ₂O ₃ 35～12％

MgO 0～4％

CaO 3～5.5％

SrO 6～9％

BaO 0～13％

MgO+CaO+SrO+BaO 17～27％

Li ₂O+Na ₂O+K ₂O 7～14％

ZrO ₂ 0.2～6％

SO ₃ 0～0.6％。

2. glass composition for substrate as claimed in claim 1, its glass transition point are more than 600 ℃.

3. according to claim 1 or claim 2 glass composition for substrate is characterized in that it is 10 that devitrification temperature is lower than viscosity ⁴Temperature during pool.

4. like claim 1,2 or 3 described glass composition for substrate, its thermal expansivity is 75～95 * 10 ^-7℃ ^-1Scope in.

5. glass composition for substrate as claimed in claim 1, % representes with weight, comprises in fact:

SiO ₂ 54～60％

A1 ₂O ₃ 6～11％

MgO 0～4％

CaO 3～5.5％

SrO 6～9％

BaO 0～13％

MgO+CaO+SrO+BaO 18～25％

Li ₂O 0～1％

Na ₂O 0～6％

K ₂O 4～12％

Li ₂O+Na ₂O+K ₂O 8～13％

ZrO ₂ 0.5～6％

SO ₃ 0～0.6％。

6. glass composition for substrate as claimed in claim 5, its glass transition point are more than 610 ℃.

7. like claim 5 or 6 described glass composition for substrate, it is characterized in that the devitrification temperature specific viscosity is 10 ⁴Temperature during pool is low more than 40 ℃.

8. like claim 5,6 or 7 described glass composition for substrate, its thermal expansivity is 80～90 * 10 ^-7℃ ^-1Scope in.

9. a plasma display is used substrate, and it uses each described glass composition for substrate in the claim 1～8.